This invention relates to sewer cleaning machines and, more particularly, to improvements in sewer cleaning machines of the character having a flexible plumbers cable or snake coiled within a rotatable drum from which the snake is withdrawn and inserted into a pipe or sewer to be cleaned and by which the snake is rotated to achieve such cleaning.
Drum type sewer cleaning machines of the character to which the present invention is directed are well known and are shown, for example, in U.S. Pat. Nos. 2,468,490 to DiJoseph; 3,095,592 to Hunt; 3,134,119 to Criscuolo; 3,246,354 to Cooney et at; 4,364,139 to Babb et al; and, 4,580,306 to Irwin. As will be seen from these patents, it is known to provide a drum type sewer cleaning machine comprising a frame structure supporting the rotatable snake drum and a drive motor arrangement for rotating the drum, and to provide for the drum to be removable from the frame and drive arrangement to, for example, facilitate replacement of the drum with one containing a snake having a different diameter. It will be further seen from the foregoing patents that such machines heretofore known often have wheels on the frames to facilitate rolling displacement of the machine from one location to another, and provide arrangements by which the wheels and frame or the frame alone supports the machine during use thereof. It will also be seen from these prior art patents that such drum type sewer cleaning machines may include a snake feeding arrangement supported by the frame and by which the snake or cable is adapted to be axially displaced relative to the drum during use of the machine.
Drum type sewer cleaning machines of the foregoing character heretofore known have a number of disadvantages attendant to the construction and use thereof. In this respect, for example, the arrangements heretofore provided for removal and replacement of the drum have been structurally complex and/or have required difficult and time consuming disassembly of component parts including the shaft supporting the drum for rotation and the bearing or bearings interposed between the shaft and drum. Moreover, such disassembly of these component parts subjects the bearings and/or support shaft to damage and/or to the ingress of dirt and other foreign matter which can produce undesirable wear upon reassembly and further use of the machine.
Another disadvantage resides in the structural interrelationship between the drum and the drive motor arrangement in those designs wherein the motor drives the drum through a roller or endless belt drivingly engaging the outer periphery of the drum. More particularly in this respect, the drive arrangement must be disengaged from the drum to facilitate removal of the drum from the frame, such as by removing the endless belt from the drum or displacing the roller from the drum. The arrangements heretofore provided in this respect have either required the cooperative efforts of two persons to achieve disengagement, have not provided desirable driving interengagement between the drum and its drive component and/or have required time consuming manual manipulation of component parts to achieve the release of the drive component. In connection with these disadvantages, for example, if the drive motor is fixed relative to the snake drum during use, as in the Criscuolo and Cooney et al patents mentioned above, it is difficult to obtain and constantly maintain uniform driving interengagement between the drive member and drum. In this respect, it is difficult to obtain a true circular contour for the drum in connection with the manufacture thereof. It is likewise difficult to obtain concentricity in connection with the mounting of the drum relative to the drum shaft about which it rotates. Either or both of these problems result in an eccentricity in the rotation of the drum which is not compensated for with a fixed motor arrangement. Further problems with regard to maintaining uniform frictional driving interengagement result from wear and stretching of the drive belt in an arrangement such as that of Cooney et al, and wear of the drive roll in an arrangement such as that of Criscuolo. While the latter problems can be overcome by a biased mounting of the motor, such as is shown in the patent to Hunt referred to above, such biasing arrangements heretofore provided are difficult to manipulate in connection with displacing the motor against the spring bias to release the belt. Thus, the cooperative effort of two persons is required to achieve detachment of the belt. This is due not only to the requirement to move the motor against the bias of two springs, but also to the fact that such movement involves the displacement of parallel support rods having a tendency to jam in the guide openings therefore.
Another disadvantage in sewer cleaning machines heretofore known resides in the snake feed mechanisms by which the plumbers snake is displaced outwardly and inwardly of the drum. Most often, the snake feeding mechanism is comprised of three rollers spaced apart to provide an opening through which the snake extends and which rollers are adapted to engage the snake so as to cause the latter to move inwardly or outwardly of the snake drum in response to rotation of the drum. Generally, two of the rollers are radially adjustable relative to the snake axis so as to enable the feed mechanism to accommodate snakes having different diameters. The third roller is generally spring biased so that the snake is firmly captured between the three rollers. Heretofore, the arrangements by which the two rollers are adjustable have been structurally complex and/or have made it extremely difficult to obtain accurate adjustment of the two rollers relative to the axis of the feed mechanism. Structural complexity not only adds to the manufacturing cost but also often makes the operation of the mechanism cumbersome. The inability to obtain accurate adjustment of the rollers relative to the axis of the feed mechanism can result in an erratic action during use of the machine, and such action imposes undesirable wear on the component parts of the snake feeding mechanism and causes instability with respect to the support of the machine during operation thereof.
Yet another disadvantage of sewer cleaning machines heretofore available relates to stabilizing the machines during use to minimize or preclude movement of the machine relative to an underlying support surface. In connection with those machines in which the frame is provided with wheels to support the machine for rolling movement along an underlying surface, the frame and wheels may be interrelated such that only the frame engages the underlying surface when the machine is in its use position. During use of the machine, the wheels are slightly elevated from the underlying surface, whereby a slight tilting of the machine from its use position provides for the wheels to engage the underlying surface to support the machine for rolling movement. Such an arrangement is shown in the patents to Babb et al and Cooney et al, mentioned above, and Cooney et al supplements such stabilizing by providing for the frame handle to be displaceable to a position engaging the underlying surface during use of the machine. Other arrangements such as shown in the patents to Hunt and Irwin provide for tilting the machine 90.degree. about a wheel axis to a use position in which the frame or frame and wheels engage the underlying surface to stabilize the machine during use. Such prior arrangements either require a somewhat complex and heavy frame structure which adds to the cost of manufacture as well as the weight of the machine, and/or require undesirable manipulations of the machine between use and non-use positions which necessitate considerable physical effort on the part of the person using the machine. The latter is especially true where such tilting displacement is 90.degree. about the wheel axis, whereby the user must exert considerable physical effort to stabilize the machine against rolling displacement along the underlying surface during such manipulation between the use and non-use positions in addition to bending over to lower the machine to or elevate the machine from the use position.